Impact of the Body Composition on Knee Osteoarthritis Assessed Using Bioimpedance Analysis

Osteoarthritis (OA) ranks among the most prevalent inflammatory diseases affecting the musculoskeletal system and is a leading cause of disability globally, impacting approximately 250 million individuals. This study aimed to assess the relationship between the severity of knee osteoarthritis (KOA) and body composition in postmenopausal women using bioimpedance analysis (BIA). The study included 58 postmenopausal females who were candidates for total knee arthroplasty. The control group consisted of 25 postmenopausal individuals with no degenerative knee joint changes. The anthropometric analysis encompassed the body mass index (BMI), mid-arm and mid-thigh circumferences (MAC and MTC), and triceps skinfold thickness (TSF). Functional performance was evaluated using the 30 s sit-to-stand test. During the BIA test, electrical parameters such as membrane potential, electrical resistance, capacitive reactance, impedance, and phase angle were measured. Additionally, body composition parameters, including Total Body Water (TBW), Extracellular Water (ECW), Intracellular Water (ICW), Body Cellular Mass (BCM), Extracellular Mass (ECM), Fat-Free Mass (FFM), and Fat Mass (FM), were examined. The study did not find any statistically significant differences in the electrical parameters between the control (0-1 grade on the K-L scale) and study groups (3-4 grade on the K-L scale). However, statistically significant differences were observed in BMI, fat mass (FM), arm circumference, triceps skinfold thickness, and sit-to-stand test results between the analyzed groups. In conclusion, the association between overweight and obesity with KOA in postmenopausal women appears to be primarily related to the level of adipose tissue and its metabolic activity.

Comparative Nanopore Sequencing-Based Evaluation of the Midgut Microbiota of the Summer Chafer (Amphimallon solstitiale L.) Associated with Possible Resistance to Entomopathogenic Nematodes

Root-feeding Amphimallon solstitiale larvae and certain other scarab beetles are the main soil-dwelling pests found in Europe, while entomopathogenic nematodes (EPN) have been used as a biocontrol agent against these species. Our study provides the first detailed characterization of the bacterial community of the midgut in wild A. solstitiale larvae, based on the nanopore sequencing of the 16S rRNA gene. In the whole dataset, we detected 2586 different genera and 11,641 species, with only 83 diverse bacterial genera shared by all studied individuals, which may represent members of the core midgut microbiota of A. solstitiale larvae. Subsequently, we compared the midgut microbiota of EPN-resistant and T0 (prior to EPN exposure) individuals, hypothesizing that resistance to this parasitic infection may be linked to the altered gut community. Compared to the control, the resistant insect microbiota demonstrated lower Shannon and Evenness indices and significant differences in the community structure. Our studies confirmed that the gut microbiota alternation is associated with resistant insects; however, there are many processes involved that can affect the bacterial community. Further research on the role of gut microbiota in insect-parasitic nematode interaction may ultimately lead to the improvement of biological control strategies in insect pest management.

Screening and Molecular Identification of Bacteria from the Midgut of Amphimallon solstitiale Larvae Exhibiting Antagonistic Activity against Bacterial Symbionts of Entomopathogenic Nematodes

Entomopathogenic nematodes (Rhabditida: Steinernematidae and Heterorhabditidae) are a group of organisms capable of infecting larvae of insects living in soil, including representatives of the family Scarabaeidae. Their insecticidal activity is related to the presence of symbiotic bacteria Xenorhabdus spp. or Photorhabdus spp. in the alimentary tract, which are released into the insect body, leading to its death caused by bacterial toxins and septicemia. Although the antibacterial activities of symbionts of entomopathogenic nematodes have been well described, there is insufficient knowledge of the interactions between these bacteria and microorganisms that naturally inhabit the alimentary tract of insects infested by nematodes. In this study, 900 bacterial strains isolated from midgut samples of Amphimallon solstitiale larvae were tested for their antagonistic activity against the selected five Xenorhabdus and Photorhabdus species. Cross-streak tests showed significant antibacterial activity of 20 isolates. These bacteria were identified as Bacillus [Brevibacterium] frigoritolerans, Bacillus toyonensis, Bacillus wiedmannii, Chryseobacterium lathyri, Chryseobacterium sp., Citrobacter murliniae, Enterococcus malodoratus, Paenibacillus sp., Serratia marcescens and Serratia sp. Since some representatives of the intestinal microbiota of A. solstitiale are able to inhibit the growth of Xenorhabdus and Photorhrhabdus bacteria in vitro, it can be assumed that this type of bacterial interaction may occur at certain stages of insect infection by Steinernema or Heterorhabditis nematodes.

Steinernema sandneri n. sp. (Rhabditida: Steinernematidae), a new entomopathogenic nematode from Poland

A new species of entomopathogenic nematodes, Steinernema sandneri n. sp., was recovered by baiting from Poland. Its morphological traits indicate that the new species is a member of the feltiae-kraussei group. A body length of 843 (708-965) μm, a more anterior position of excretory pore (56 μm), and the lower D% value (40 vs > 46) discriminate this species from most of the other group members. The first-generation males of S. sandneri n. sp. can be distinguished from the other clade members by a 60 μm long spicule, a relatively long gubernaculum (GS% = 79), and the position of the excretory pore (80 μm). Phylogenetic analysis of the ITS rDNA, D2D3 of 28 S rDNA, and cox1 sequences confirmed that S. sandneri n. sp. is a new species of the feltiae-kraussei group, closely related to S. kraussei and S. silvaticum.

Gum Arabic/Gelatin and Water-Soluble Soy Polysaccharides/Gelatin Blend Films as Carriers of Astaxanthin-A Comparative Study of the Kinetics of Release and Antioxidant Properties

Polymer blending and incorporation of active substances offer a possibility of generation of novel packaging materials with interesting features. Astaxanthin is one of the most powerful antioxidants. Hence, in this study, water-soluble AstaSana astaxanthin (AST) was incorporated into 75/25 gum arabic/gelatin (GAR75/GEL25) and water-soluble soy polysaccharides/gelatin (WSSP75/GEL25) blend films in different concentrations (0, 0.25%, 0.5%, 1%). Microscope images showed good compatibility between the polysaccharides and GEL. Basing on time required for 50% release, the WSSP-based film exhibited an approximately four-fold slower release rate (t_50% = 65.16–142.80 min) than the GAR-based film (t_50% = 14.64–34.02 min). This result was mainly ascribed to the slower dissolution of the WSSP-based carrier. The faster release rate of the GAR-based films resulted in stronger antioxidant activity (quarter-scavenging time (t_25%ABTS) = 0.22–7.51 min) in comparison to the WSSP-based films (t_25%ABTS = 0.91–12.94 min). The increase in the AST concentration was accompanied by gradually reduced solubility and the release rate. It is possible that the increasing number of starch granules (from the AST formulation) acted as a dissolution blocking agent. In general, the WSSP75/GEL25 film displayed the most linear (the Zero-order similar) release profile. So, this carrier has potential for release of AST at a quasi-constant speed.

Bacteria from the Midgut of Common Cockchafer (Melolontha melolontha L.) Larvae Exhibiting Antagonistic Activity Against Bacterial Symbionts of Entomopathogenic Nematodes: Isolation and Molecular Identification

The mechanisms of action of the complex including entomopathogenic nematodes of the genera Steinernema and Heterorhabditis and their mutualistic partners, i.e., bacteria Xenorhabdus and Photorhabdus, have been well explained, and the nematodes have been commercialized as biological control agents against many soil insect pests. However, little is known regarding the nature of the relationships between these bacteria and the gut microbiota of infected insects. In the present study, 900 bacterial isolates that were obtained from the midgut samples of Melolontha melolontha larvae were screened for their antagonistic activity against the selected species of the genera Xenorhabdus and Photorhabdus. Twelve strains exhibited significant antibacterial activity in the applied tests. They were identified based on 16S rRNA and rpoB, rpoD, or recA gene sequences as Pseudomonas chlororaphis, Citrobacter murliniae, Acinetobacter calcoaceticus, Chryseobacterium lathyri, Chryseobacterium sp., Serratia liquefaciens, and Serratia sp. The culture filtrate of the isolate P. chlororaphis MMC3 L3 04 exerted the strongest inhibitory effect on the tested bacteria. The results of the preliminary study that are presented here, which focused on interactions between the insect gut microbiota and mutualistic bacteria of entomopathogenic nematodes, show that bacteria inhabiting the gut of insects might play a key role in insect resistance to entomopathogenic nematode pressure.

Evolution and taxonomy of nematode-associated entomopathogenic bacteria of the genera Xenorhabdus and Photorhabdus: an overview

Entomopathogenic bacteria from the genera Photorhabdus and Xenorhabdus are closely related Gram-negative bacilli from the family Enterobacteriaceae (γ-Proteobacteria). They establish obligate mutualistic associations with soil nematodes from the genera Steinernema and Heterorhabditis to facilitate insect pathogenesis. The research of these two bacterial genera is focused mainly on their unique interactions with two different animal hosts, i.e. nematodes and insects. So far, studies of the mutualistic bacteria of nematodes collected from around the world have contributed to an increase in the number of the described Xenorhabdus and Photorhabdus species. Recently, the classification system of entomopatogenic nematode microsymbionts has undergone profound revision and now 26 species of the genus Xenorhabdus and 19 species of the genus Photorhabdus have been identified. Despite their similar life style and close phylogenetic origin, Photorhabdus and Xenorhabdus bacterial species differ significantly in e.g. the nematode host range, symbiotic strategies for parasite success, and arrays of released antibiotics and insecticidal toxins. As the knowledge of the diversity of entomopathogenic nematode microsymbionts helps to enable the use thereof, assessment of the phylogenetic relationships of these astounding bacterial genera is now a major challenge for researchers. The present article summarizes the main information on the taxonomy and evolutionary history of Xenorhabdus and Photorhabdus, entomopathogenic nematode symbionts.

Microsporidia Nosema spp. - obligate bee parasites are transmitted by air

Microsporidia Nosema are transferred among bees via the faecal-oral route. Nosema spp. spores have been detected on flowers and transferred to hives along with the bee pollen. The aim of the present study was to determine whether Nosema microsporidia are transferred by air in an apiary, in a control area (without the presence of bee colonies), and/or in a laboratory during cage experiments with artificially infected bees. The novel way of transmission by air was investigated by the volumetric method using a Hirst-type aerobiological sampler located on the ground in the apiary, in the Botanical Garden and on the laboratory floor. Concurrently, the mean rate of Nosema infections in the foragers in the apiary was estimated with the Bürker haemocytometer method. Spore-trapping tapes were imaged by means of light microscopy, Nomarski interference contrast microscopy and scanning electron microscopy. The highest concentration of Nosema spores per 1m3 of air (4.65) was recorded in August, while the lowest concentration (2.89) was noted in July. This was confirmed by a Real-Time PCR analysis. The presence of N. apis as well as N. ceranae was detected in each of the tested tapes from the apiary. The average copy number of N. apis was estimated at 14.4 × 104 copies per 1 cm2 of the tape; whereas the number of N. ceranae was 2.24 × 104 copies per tape per 1 cm2. The results indicate that Nosema microsporidia were transferred by the wind in the apiary, but not in the Botanical Garden and laboratory by air. This was confirmed by genetic analyses. DNA from immobilised biological material was isolated and subjected to a PCR to detect the Nosema species. A fragment of the 16S rRNA gene, characteristic of Nosema apis and N. ceranae, was detected. Our research adds knowledge about the transfer of Nosema spp. microsporidia in the natural environment and indicates the season associated with the greatest risk of a bee colony infection with Nosema spp.

A simplified method of preparation of mammalian intestine samples for scanning electron microscopy

Due to strong tissue hydration and complex architecture of the mucous membrane, appropriate preparation of inhomogeneous gastrointestinal tissues, especially from the intestine, for scanning electron microscopy is still a challenge and requires constant improvement of preparation techniques. In this article, we describe a simplified method of preparation of small intestinal mucosa tissues for observations in a scanning electron microscope. We emphasized the most important points in the preparation process that, when ignored, may result in formation of numerous artifacts and the inability to analyze the samples reliably. The developed technique facilitates proper animal tissue sampling in the field conditions, reducing the time of tissue collection and sample preparation as well as the total process costs. The fixative of choice, that is, buffered formalin, fixes, and stiffens the processed tissues properly, which is especially important in preservation of long, highly hydrated intestinal villi without shrinkage artifacts. The method described has been successfully used in comparative studies of the development of small intestines in mammals (pigs, mice, rats), reptiles, and birds (hens).

Steinernema poinari (Nematoda: Steinernematidae): a new symbiotic host of entomopathogenic bacteria Xenorhabdus bovienii

Three strains of symbiotic bacteria were isolated from an entomopathogenic nematode Steinernema poinari retrieved from soil in eastern Poland. Using 16S rDNA, recA, gltX, gyrB, and dnaN gene sequences for phylogenetic analysis, these strains were shown to belong to the species Xenorhabdus bovienii. The nucleotide identity between the studied S. poinari microsymbionts and other X. bovienii strains calculated for 16S rDNA and concatenated sequences of four protein-coding genes was 98.7-100% and 97.9-99.5%, respectively. The phenotypic properties of the isolates also supported their close phylogenetic relationship with X. bovienii. All three tested X. bovienii strains of different Steinernema clade origin supported the recovery of infective juveniles and subsequent development of the nematode population. However, the colonization degree of new infective juvenile generations was significantly affected by the bacterial host donor/recipient. The colonization degree of infective juveniles reared on bacterial symbionts deriving from a non-cognate clade of nematodes was extremely low, but proved the possible host-switching between non-related Steinernema species.

Mechanisms involved in the development of the small intestine mucosal layer in postnatal piglets

The use of complementary visualization and measurement techniques allowed accurate description and quantification of changes in the intestinal mucosal architecture and provided a comprehensive outlook on the dynamics of remodelling and maturation processes of the mucosal layer taking place in the small intestine of piglets from birth to weaning. The aim of the study was to examine the early postnatal development of the small intestine in pigs. Three techniques were used: scanning electron microscopy (measurements of villus density and shape, height of enterocytes and microvilli, cell exfoliation, and location of extrusion zones), optical microscopy (cross section, measurement of structures: villus length and width; crypt depth; mucosal thickness), and confocal microscopy (cell localization, apoptosis, exfoliation and migration). The postnatal development of the mucosal layer of the small intestine was reflected in changes in the density, length, width, and shape of villi, crypt depth, replacement of enterocyte population, and arrangement. The presence of deep transverse furrows on villus corpus and vacuolated fetal-type enterocytes in the mucosal layer of the small intestine, which are able to engulf large amounts of colostrum shortly after birth, appears to play an important role in the observed phenomenon of straightening of the villus height and increasing of the villus diameter shortly after birth. We hypothesized that the intestinal mucosal layer is compressed before birth and ready to unfold within a short time after birth.

Strains of Photorhabdus spp. associated with polish Heterorhabditis isolates: their molecular and phenotypic characterization and symbiont exchange

The relationships between six bacterial symbionts of the entomopathogenic nematodes Heterorhabditis bacteriophora and Heterorhabditis megidis from Poland to species and subspecies of the genus Photorhabdus were evaluated. This study was based on phylogenetic analysis of sequence data of five genes: 16S rRNA, gyrB, recA, gltX, and dnaN. The bacteria were also characterized phenotypically by biochemical and physiological tests. Our results have revealed that the Photorhabdus strains isolated from H. megidis belong to P. temperata, subsp. temperata and subsp. cinerea. Isolates from H. bacteriophora represent P. luminescens subs. kayaii and P. temperata subs. cinerea. This study for the first time provides evidence for H. bacteriophora and P. temperata subsp. cinerea symbiotic association. In addition, we tested whether the microsymbionts of the Polish H. bacteriophora and H. megidis isolates support the development of non-native nematode host population and colonization of their infective juveniles. It has been shown that the studied Photorhabdus strains can readily swap their nematode host, both at intra- and interspecies level. It supports the hypothesis of different symbiotic associations in the Heterorhabditis-Photorhabdus lineage.

Intestinal MMC-related electric fields and pancreatic juice control the adhesion of Gram-positive and Gram-negative bacteria to the gut epithelium--in vitro study

The adhesion of six different Lactobacillus and Lactococcus and three pathogenic Escherichia and Salmonella strains was studied using Caco-2 cell line. In this in vitro model system the influence of weak electric field (EF) on bacterial adhesion was tested. The EF source was the in vitro reconstruction of spiking potentials recorded in the duodenum of a healthy calf during one myoelectrical migration complex (MMC) cycle. The ability to adhere to Caco-2 cells of bacteria belonging to two groups, Gram-positive lactobacilli and lactococci, and Gram-negative Escherichia and Salmonella differed considerably. The pathogenic bacteria adhered better to well-differentiated Caco-2 cells whereas lactobacilli and lactococci displayed better adhesion to non-differentiated Caco-2 cells. In the presence of MMC-related EF an increased adhesion of Lactobacillus and Lactococcus but not of Salmonella enterica s. Enteritidis and E. coli 269 to Caco-2 cells was observed. Two later strains adhered even less in the presence of EF. The same tendency was found in the presence of pancreatic juice in a cell medium. In conclusion, the myoelectric component of the small intestinal motility, the MMC-related EF, and pancreatic juice may increase the ability of lactic acid bacteria to adhere to GI epithelial cells, creating better environmental conditions for colonization of the intestine and competition with Gram-negative pathogens.

Gradual disappearance of vacuolated enterocytes in the small intestine of neonatal piglets

The unique feature of enterocytes in newborn mammals is the presence of an apical canalicular system (ACS) leading to production of large vacuoles, important for colostral macromolecule uptake. The vacuolated fetal-type enterocytes (VFE) enable transfer of colostral and milk proteins from the intestinal lumen across the epithelium without loosing their biological activity. First VFE are observed in the pig and lamb fetuses in the second trimester of pregnancy, located at the upper part of villi in the proximal region of the fetal small intestine and subsequently in the middle and distal regions. After birth the VFE are replaced with enterocytes lacking ACS. The present study aimed to investigate the depletion of VFE in the small intestine in the sow reared pig neonates during the first postnatal weeks using scanning electron microscopy (SEM). The SEM analysis demonstrated the gradual disappearance of vacuolated enterocytes in time. VFE remained in the jejunum for a few days after birth, whereas in the duodenum single VFE were present only at birth. In the proximal jejunum, the VFE were localized in the upper part of the villi, and disappeared until the day 3 of life. VFE were present in the mid and distal jejunum, and diminished gradually until day 14 of life. By the day 21 of life, the vacuolated cells were not observed neither in the jejunum nor ileum. In conclusion, morphology analysis of pig small intestinal mucosa suggests that replacement of fetal type vacuolated enterocytes is resumed within 21 days after birth.

Content of 5-alpha-reductase (type 1 and type 2) mRNA in dermal papillae from the lower abdominal region in women with hirsutism

BACKGROUND

Androgens influence the growth of terminal hair. The dermal papilla contains androgen receptors and the enzymes 5-alpha-reductase types 1 and 2. Both of these enzymes convert testosterone to the more active androgen, 5-alpha-dihydrotestosterone. The male distribution pattern of terminal hair in females is termed hirsutism. It is most common among women with hyperandrogenism; however, it may also affect patients with normal androgen levels (idiopathic hirsutism).

OBJECTIVES

The aim of this study was to assess the expression of 5-alpha-reductase types 1 and 2 mRNA in dermal papillae from the lower abdominal skin in women with hirsutism.

METHODS

The study included 42 subjects, 24 with a diagnosis of polycystic ovary syndrome (PCOS) and 18 with idiopathic hirsutism (IH). In all patients, free serum testosterone was measured.

RESULTS

The mean +/- SD concentration of free serum testosterone was 7.2 +/-5.3 pmol/L in the total group of patients, 10.8 +/- 4.0 pmol/L in patients with PCOS, and 2.5 +/- 1.7 pmol/L in patients with IH. Quantitative analysis was then performed for the mRNA of 5-alpha-reductase types 1 and 2, both of which were found within the dermal papillae from the lower abdominal skin region. The number of mRNA copies/microg of total RNA for 5-alpha-reductase type 1 was statistically significantly higher than that for type 2 in both groups of examined patients. We also demonstrated a positive correlation between the number of mRNA copies/microg of total RNA for 5-alpha-reductase types 1 and 2 and the concentration of free serum testosterone in women with PCOS and IH. Considering all patients together, we found a positive correlation between the number of mRNA copies/microg of total RNA for 5-alpha-reductase type 2 and the concentration of free serum testosterone. There was also a tendency towards a positive correlation between the number of mRNA copies/microg of total RNA for 5-alpha-reductase type 1 and the concentration of free serum testosterone.

CONCLUSION

The results of our study suggest that testosterone increases expression of 5-alpha-reductase types 1 and 2 in dermal papillae from the lower abdominal region in patients with hirsutism.

Light and scanning electron microscopy evaluation of the postnatal small intestinal mucosa development in pigs

Modifications in the structure of gastrointestinal mucosa is often used to evaluate gut function for instance during the development or in response to particular food components. Scanning electron microscopy (SEM) gives a chance to observe the surface of the gut epithelium in three dimensions. However, this technique is seldom used due to technical difficulties. The present study attempted to investigate the intestinal mucosa structure changes in the postnatal pig using light and scanning electron microscopy technique. Experiments were carried out on sow reared piglets from birth until 38 days of age. Piglets were sacrificed at birth and at the 3(rd), 7(th), 21(st) and 38(th) day of life. The entire gastrointestinal tract was immediately harvested and the whole thickness tissue samples were taken from the duodenum, jejunum and ileum for optical and scanning electron microscopy. SEM analyses corroborated with histometry made by optical microscopy. Moreover, a number of shape modifications of the villi and its surface have been observed. The development changes in small intestine mucosa during the first 3 weeks were manifested in shape, size and density of villi. In conclusion, the structure of small intestinal mucosa undergoes profound structural changes. SEM gives a new dimension in the investigation of gut mucosa.

Deuterium-oxide-induced histamine release from basophils of allergic subjects. I. Responsiveness to deuterium oxide requires an activation step

Basophils from many atopic persons, and especially asthmatic patients, have been shown to release histamine in response to 44% deuterium oxide (D2O), whereas basophils from nonatopic persons do not release histamine. The present experiments analyzed the mechanisms by which D2O mediated release. It was found that although D2O induced release from washed leukocytes, it failed to induce release from whole blood or from leukocytes that had sedimented but had not been washed. The kinetics of release after washing were rapid and were equivalent regardless of the temperature at which cells were sedimented (O degrees or 37 degrees C). Washed cells became desensitized to the action of D2O within 30 to 60 min at 37 degrees C, whereas unwashed leukocytes did not become desensitized. Serum or plasma inhibited D2O-induced release, although high concentrations (1/5) were less inhibitory than lower ones (1/10 to 1/100). Basophils from D2O responders also released histamine in response to a "platelet enhancing factor" (PEF), whereas those from D2O nonresponders did not. As with D2O-mediated release, PEF-mediated release occurred only with washed leukocytes, desensitized within 30 to 60 min at 37 degrees C, and was inhibited by serum. These results suggest that D2O induces histamine release by augmenting the effects of an endogenous activation mechanism, and that PEF acts on the same (D2O-responsive) donors to augment this activation mechanism. Cell activation, as well as desensitization of this activation mechanism, occurs rapidly when basophils are washed free of plasma inhibitors and placed at 37 degrees C.

An antigen-activated DFP-inhibitable enzyme controls basophil desensitization

Diisopropyl fluorophosphate (DFP), an inhibitor of serine esterases, enhances IgE-mediated histamine release from human basophils and blocks the desensitization process (i.e., the antigen-induced hyporesponsiveness) in these cells. Both activities occur at relatively low concentrations of DFP (0.1 to 0.5 mM) and are dependent on an antigen-activated intracellular event: if DFP is removed before antigen addition, it has neither effect. Neither hydrolyzed DFP nor the non-phosphorylating diisopropyl methyl phosphate enhanced histamine release or blocked desensitization. In addition to providing a demonstrable biochemical correlate of desensitization, our data suggest that the desensitization process controls the release of mediators of allergic reactions.

An antigen-activated DFP-inhibitable enzyme controls basophil desensitization

Diisopropyl fluorophosphate (DFP), an inhibitor of serine esterases, enhances IgE-mediated histamine release from human basophils and blocks the desensitization process (i.e., the antigen-induced hyporesponsiveness) in these cells. Both activities occur at relatively low concentrations of DFP (0.1 to 0.5 mM) and are dependent on an antigen-activated intracellular event: if DFP is removed before antigen addition, it has neither effect. Neither hydrolyzed DFP nor the non-phosphorylating diisopropyl methyl phosphate enhanced histamine release or blocked desensitization. In addition to providing a demonstrable biochemical correlate of desensitization, our data suggest that the desensitization process controls the release of mediators of allergic reactions.

On the mechanism of histamine release from sodium fluoride-activated mouse mast cells

We have found that sodium fluoride-induced histamine release from mouse mast cells occurs in two separate steps, activation in the presence of fluoride and absence of calcium, and secretion triggered by calcium. The amount of released histamine was dependent either on the time of cell exposure to fluoride or on the final fluoride concentration in the incubation medium. The secretory step depends on the concentration of extracellular calcium; it increased as the concentration of calcium was increased. However, a substantial part of the release was both calcium and energy independent. This part, probably cytotoxic, increased markedly at the highest concentration and with extended times of cell exposure to fluoride. Among other divalent cations tested only strontium could partly substitute calcium to trigger secretion. The activating action of fluoride slowly decayed with time and addition of calcium for up to 2 h caused histamine release. Both steps were dependent on temperature and pH and were inhibited by antimycin A, suggesting that the reaction was enzymatic. The action of fluoride on mouse mast cells closely resembles its action on rat mast cells; however, some differences were also observed.

The histamine-induced skin reaction in schizophrenic and normal subjects

Most published data on histamine skin tests on schizophrenic patients show them to be insensitive relative to normals or other psychotic patients. However, experimental conditions have varied and in most cases only a single dose of histamine was used. We have compared 13 volunteer controls and 16 paranoid schizophrenics; each subject was injected intradermally with histamine, 10, 20, and 50 microgram, doses predetermined in volunteers to give a dose-response curve. Wheal and flare were measured at 10 and 20 minutes, intervals near the time of maximum flare. We found no statistically significant differences between normal controls and schizophrenic patients.

A modulation of the anaphylactic basophil histamine release by selective H2 histamine agonists

Two selective H2-histamine agonists, dimaprit and impromidine, have been tested for their action on histamine release from human basophils and rat mast cells. IgE-mediated basophil histamine release was inhibited by stimulation of histamine H2-receptors. However, differences between the actions of both dimaprit and impromidine were noticed. Both impromidine and dimaprit had no specific effect on 48/80-induced histamine release from rat mast cells, although the latter in higher concentrations either slightly increased spontaneous histamine release or non-specifically inhibited compound 48/80-induced release. The results are consistent with the view that activation of adenylate cyclase via H2-histamine receptors might be an important regulatory mechanism of histamine release from human basophils but not from rat mast cells.

New light on the mechanism of action of disodium cromoglycate

Disodium cromoglycate (DSCG) shows a prolonged protective effect against histamine on the smooth muscle of guinea pig ileum. Preventing allergen-induced mediator release from mast cells as well as protection of smooth muscle against mediators already released can both explain a beneficial effect of DSCG in the treatment of bronchial asthma and food allergy. It is believed that disappointing clinical trials with many new anti-allergic drugs, e.g. RS 7540, can be explained by the lack of protective effect on the smooth muscle of target organs.

The histamine releasing properties of some agents used in textile industry

The inflammatory effect of some compounds (polyglycolamines and polyglycolalcohols condensated with various number of ethylene oxide groups) used in textile industry were investigated as to their action on skin vascular permeability in rats and histamine release from rat peritoneal mast cells. The intradermal injection of tested agents caused the inflammatory skin reactions of various intensity depending on time, dose and chemical structure of agent used. It has been also shown that these properties of tested compounds were correlated with their histamine releasing activity and seemed to be dependent on their chemical structure, namely, the number of ethylene oxide groups in molecule. It is suggested that the histamine release induced by tested compounds is of cytotoxic nature since it depends neither on metabolic energy nor on extracellular calcium.

On the mechanism of suppressive action of some drugs influencing calcium ions on the histamine-induced contraction of guinea-pig ileum

The effects of procaine, verapamil, EDTA, pyridoxine and disodium cromoglycate (DSCG) on histamine-induced contractions of isolated guinea-pig ileum have been compared. Procaine, verapamil, EDTA and DSCG exerted the protective action on the ileum against histamine either when the drugs were present in the organ bath or after they were washed out. This effect was dose- and time-dependent and reversible. On the other hand, the protective effect of pyridoxine against histamine-induced contraction of ileum disappeared quickly after removing of drug from the bath. It is suggested that all tested agents influence calcium utilization by muscle cells.

A protective action of disodium cromoglycate against the contraction of guinea-pig ileum induced by various pharmacological stimulants

The effect of disodium cromoglycate (DSCG) on the contraction of isolated guinea-pig ileum induced by histamine, acetylcholine and serotonin has been investigated. DSCG protected ileum against all agents tested. The action of DSCG at concentrations of 10(-3) to 10(-2) M was both dose- and time-dependent. Furthermore, DSCG inhibited compound 48/80-induced histamine release from isolated mast cells over the same range of concentrations. The anti-histaminic action of DSCG was reversible and after 2 h the ileum responded normally to histamine. DSCG-induced inhibition of the contractile response to histamine could be overcome by increasing concentrations of histamine but not by extracellular calcium. A mechanism of the action of DSCG, either against the contraction of ileal smooth muscle or against histamine release from mast cells, is discussed with a view to the inhibition of the utilization of calcium ions by both cells.

Failure of acetylcholine to release histamine from rat mast cells

The action of various salts of acetylcholine on isolated mast cells from Wistar and F1 hybrids of Wistar and August rats was investigated. None of the acetylcholine salts within the concentration range 10(-12) M to 10(-2) M was able to release histamine either from Wistar or from hybrid mast cells. Compound 48/80, used as a control, was active in both cases. The results obtained are in opposition to some recent reports. The possible reasons for these contradictions are discussed.

The mechanism of histamine release induced by the ionophore X537A from isolated rat mast cells. II. The relationship between increase of cell volume and histamine release

The ionophore X537A induced swelling of isolated rat mast cells parallel to histamine release. Both actions were depressed by extracellular calcium and BSA, temperatures below 37 degrees C, NEM, PMSF, and TTX, and were enhanced by high potassium and pretreatment of the cells with ATP. DSCG, theophylline, and DFP enhanced the histamine release noted after 10 min of incubation without influencing the swelling action of X537A. The swelling action could not be separated from histamine release and it is suggested that it might be inherent in the mechanism of secretion induced by X537A. The present results further distinguish histamine release induced by the two ionophores X537A and A23187.

The mechanism of histamine release induced by the ionophore X537A from isolated rat mast cells. I. Significance of monovalent cations, calcium, metabolic energy and temperature

Histamine release induced by X537A from isolated rat mast cells was dependent on the presence of sodium or potassium but not on calcium in the incubation medium. The rate of release was faster in potassium than in sodium, but the final release was the same after prolonged incubation. Extracellular calcium as well as metabolic inhibitors depressed the rate or release induced by X537A. Pretreatment of mast cells with either EDTA or the ionophore A23187 in the absence of extracellular calcium did not influence subsequent release induced by X537A. The findings of release at 45 degrees C and lack of release at 0 degrees C distinguish the mechanism of action of X537A from calcium- energy-dependent releasing agents like compound 48/80 and A23187 on the one hand and the simple lytic action of decylamine on the other.

Mechanism of histamine release induced by the ionophore X537A from isolated rat mast cells

X537A released histamine from isolated histamine-retaining mast cell granules incubated at 37 degrees C in Tris-sodium (150 mM) or Tris-potassium (150 mM), but not in Tris-glucose (300 mM). The release was depressed at 0 degrees C. In contrast, decylamine released all histamine bound to the granules irrespective of the presence of monovalent cations in the incubation medium of temperature. X537A did not release histamine from an artificial heparin-protamine complex when incubated in deionized water. The mechanism of histamine release by X537A can be explained by the ability of the ionophore to carry monovalent cations across cellular membranes, hereby making the ions available for exchange with histamine bound to the granular matrix. This mechanism can be distinguished from that of agents triggering an exchange between cations and bound histamine through a calcium- and energy-dependent exocytotic process on the one hand and through membrane lysis on the other. Based on the observation that the ionophore was able to carry histamine into the bulk of an organic phase, various possibilities exist to explain how histamine escapes from the cells following release from intracellular granular stores.

Histamine release by calcium from sodium fluoride-activated rat mast cells. Further evidence for a secretory process

Histamine release induced by calcium (step 2) from fluoride-activated (step 1) rat mast cells was found to be dependent on temperature and pH. Whereas the influence of temperature was different on the two steps, the pH effects were similar. The activation of the cells by fluoride occurred faster at low pH. Agents considered to influence cyclic nucleotide content of the cells neither influenced fluoride activation nor the secretory action of calcium, except for theophylline which inhibited the second step and shared this effect with lidocaine and several other agents known to act as inhibitors of histamine secretion. The time course for the action of fluoride to inhibit subsequent histamine release by compound 48/80 in the absence of extracellular calcium was somewhat faster than its action to activate the cells to the secretory action of calcium. In the absence of calcium, no cyclic AMP could be detected in the cells. In the presence of 1 m<i>M</i> calcium, 2.5 pmol/10⁶ cells cyclic AMP was found which decreased by the presence of fluoride. No uptake of ⁴⁵Ca was observed in fluoride-activated mast cells in the absence of release. Furthermore, fluoride did not activate isolated mast cell granules to release histamine when challenged with calcium. The results suggest that calcium-induced histamme secretion from fluoride-activated cells conforms to a secretory system which, in many respects, is governed by similar regulatory factors as for antigen and other secretagogues.

Sodium fluoride--a stimulus for a calcium-triggered secretory process

Calcium triggers the secretion of histamine from mast cells after previous exposure of the cells to sodium fluoride. The secretory process can be divided into a fluoride-activating step and a calcium-induced secretory step dependent on cellular metabolic energy. The secretory response induced by compound 48/80 in the absence of extracellular calcium was found to decrease after fluoride pretreatment of the cells. The response was, however, unaffected, provided calcium was introduced to the cells simultaneously with compound 48/80.